Syringe with integrally formed piercing member and luer slip

ABSTRACT

A syringe for use in vaccine reconstitution or rehydration has a barrel ( 1 ) having a plunger ( 2 ) in slidable and sealing engagement therein, and a piercing member ( 3 ) formed integrally with the barrel. The piercing member ( 3 ) has a bore ( 10 ) in communication with the distal end of the barrel, and a piercing point ( 12 ) and aperture ( 13 ) at its distal end. The distal end of the piercing member ( 3 ) has an external taper which comprises a male luer part ( 15 ) compatible with an infusion set. The length of the distal end of the piercing member ( 3 ) distally of a predetermined attachment diameter of the male luer part ( 15 ) is chosen so that it cannot fit a standard metal syringe needle, as the end of the piercing member ( 3 ) engages with another part of the metal needle before the female luer part on the needle reaches the attachment diameter. The syringe is easy to use for rehydration, but cannot be used for normal injections.

The present invention relates to syringes, and in particular to syringesfor use in reconstitution or rehydration.

For reconstitution of anhydrous vaccines a specific amount of diluent isused to reconstitute the dried vaccine, which is provided in a containersealed by a rubber septum. The septum is pierced by a metal needle of asyringe containing the diluent, which is then injected into thecontainer to reconstitute the dried vaccine. Then a number of othersyringes (typically ten) are used to pierce the septum again to draw upthe correct amount of reconstituted vaccine for injection. The repeatedpiercings tend to shred the septum, which may result in leakage ofvaccine, and/or possible contamination. An alternative is to pierce theseptum once with metal needle of a syringe, and then leave the needlein, while detaching the syringe body, allowing further syringe bodies tobe attached sequentially to draw up the correct amount of vaccine intoeach syringe. This alternative is fiddly and time-consuming, and alsorisks contamination.

Rehydration of a dehydrated person requires a regular injection of asaline or similar solution. A catheter of an infusion set is insertedinto the person. The infusion set has a female luer part, that is, aslightly tapered conical bore into which fits a correspondingly taperedmale projection. Saline solution is drawn up from a container into asyringe fitted with a standard metal needle which pierces the containerseal. The needle is then removed from the syringe, which has aprojection on the barrel adapted to fit the female luer bore on theinfusion set. Once the syringe is attached to the infusion set by theluer arrangement, the saline solution can be injected. Again thisprocedure is somewhat fiddly and time-consuming, and carries a risk ofcontamination.

US-A-2002/0065490 shows a syringe for transferring a medical substancefrom a container with a rubber septum to a container, using a piercingmember which may be formed integrally with the syringe barrel. Thepiercing member fits onto a standard metal syringe needle.

According to the present invention, we provide a syringe comprising abarrel having a plunger in slidable and sealing engagement therein, anda piercing member formed integrally with the barrel, the piercing memberhaving a bore in communication with the distal end of the barrel, and apiercing point and an aperture at its distal end, the distal end of thepiercing member being formed with an external taper comprising a maleluer part compatible with an infusion set, the length of the distal endof the piercing member distally of a predetermined attachment diameterof the male luer part being chosen so that the end of the piercingmember engages with a part of a standard metal syringe needle before afemale luer part on the needle reaches the attachment diameter.

The syringe of the invention may therefore be used for rehydrationpurposes, to pierce a seal of a container and draw up a solution, andthen to connect directly to an infusion set, using the luer connection,for injection of the solution. It has the advantages that it is easy touse, and reduces the risk of contamination. It cannot be used for normalinjections, as it will not fit a standard metal syringe needle, thusreducing the risk of incorrect injections.

The syringe barrel and piercing member may be moulded in one piece, froma suitable plastics material. One such material is polypropylene, whichhas sufficient rigidity to make the piercing point, although the pointwill degrade with use. The point will not be suitable for piercing theskin of a human or animal body at all.

The taper angle of the male luer part of the piercing member ispreferably about 6°, at an appropriate attachment diameter, to fit astandard infusion set.

The barrel may have at its distal end a reduced diameter portion, towhich the piercing member is attached. The external diameter of thepiercing member is conveniently slightly less than the reduced diameterportion of the barrel. A protective cap may then fit over the piercingmember, and be retained by the reduced diameter portion of the barrel.

The plunger preferably comprises a rod carrying a head, on which ismounted a seal for engagement with the internal surface of the barrel. Aprojection is formed on the distal side of the plunger head, theprojection fitting into the bore of the piercing member as the plungeris moved distally. The projection ensures that there is no dead space inthe syringe, and enables an accurate amount of liquid to be drawn intothe barrel and subsequently dispensed. This has the advantage that thesyringe can also be used to reconstitution of vaccines, where it isimportant that an accurate amount of diluent is used.

An embodiment of the invention is illustrated, by way of example only,in the accompanying drawings, in which:

FIG. 1 shows a side view of a syringe; and

FIG. 2 is a perspective view of the syringe of FIG. 1, showing aprotective cap in place.

The syringe shown in the Figures comprises a barrel 1 in which works aplunger 2, and a piercing member 3 formed integrally with the barrel 1.

The barrel 1 is generally cylindrical, having a main cylinder 4, with aninner cylindrical surface 5 in which the plunger 2 slides sealingly. Theproximal end 6 of the barrel 1 is open, and is provided with a grippingflange 7. The distal end has a reduced diameter portion 8, with the stepbetween the main cylinder 4 and the reduced diameter portion 8 formingan internal abutment shoulder 9. In a standard syringe the reduceddiameter portion 8 would have an open end to define a liquid outlet, anda metal needle would be fitted onto the reduced diameter portion 8 inany suitable way. Examples of fittings are a luer slip, which holds theneedle as a friction fit, a luer lock onto which the needle screws, or apermanent fixing by means of glue or the like. In the syringe of theinvention, as shown, the reduced diameter portion 8 is attached insteadto the piercing member 3.

The piercing member 3 is a substantially cylindrical member having abore 10 whose proximal end 11 is in communication with the interior ofthe barrel 1. At its distal end the member 3 has a sharp piercing point12 and an aperture 13 forming a liquid inlet/outlet. The externalsurface 14 of the distal end is formed with a cylindrical inward taperof about 6°, which forms a male luer part 15 of a standard attachmentdiameter adapted to fit into the female luer part of a standard infusionset (not shown). The luer connection is of the luer slip type, where theparts are held by friction. The male luer part 15 will not attach to astandard metal needle (not shown), because of the length of the point 12distally of the luer part 15. If a standard metal needle is put on tothe point 12, the distal end will engage another part of the needle hubbefore the male luer part 15 engages the female luer part of the needleat the attachment diameter.

The barrel 1 and piercing member 3 are moulded in one piece, frompolypropylene. The polypropylene can be moulded with sufficient rigidityto make the sharp piercing point 12. The point 12 will not be suitablefor piercing skin, so the syringe cannot be used for direct injectioninto the human or animal body. The point 12 will degrade with use, butwill typically be able to pierce a rubber septum up to six times.

The plunger 2 comprises a rod 16 having a finger plate 17 at itsproximal end and at its distal end a head 18 to which is mounted anelastomeric seal 19 forming a complete seal with the inner surface 5 ofthe barrel 1. A projection 20 is formed on the distal side of theplunger head 18. The projection 20 is substantially cylindrical, and isshaped to correspond to the internal bore of the reduced diameterportion 8 and the bore 10 of the piercing member 3. Then, with theplunger 2 fully depressed so that the seal 19 engages the abutmentshoulder 9, the projection 20 is fully received in the reduced diameterportion 8 and the bore 10 of the piercing member 3. This ensures thatthere is no dead space, so that all liquid in the syringe will bedispensed when the plunger 2 is fully depressed. The barrel 1 may have ascale (not shown) to indicate the volume that it contains.

The head 18 of the plunger 2 may also have a locking member 21. Thelocking member 21 normally slides in the barrel 1 with the head 18, butif it passes over a projection 22 on the inner surface 5 at the distalend of the barrel 1, the locking member 21 engages behind the projection22 on a withdrawal movement of the plunger 2 to lock it and preventfurther withdrawal. The locking member 21 will only operate if theplunger 2 is fully depressed.

FIG. 2 shows the syringe fitted with a protective cap 23. The cap 23 issubstantially the same shape as the piercing member 3, and fits over it,being retained frictionally by engagement with the reduced diameterportion 8.

For rehydration use the cap 23 is removed from the syringe, and with theplunger 2 in its rest position the piercing point 12 is used to pierce aseal such as a rubber septum of a container (not shown) holding a salineor other rehydration solution. The plunger 2 is then withdrawn to drawup solution into the barrel 1 through the opening 13 and the bore 10.The piercing member 3 is then withdrawn from the container, and the cap23 put on it, if necessary. The syringe can then be taken to a patientwho has previously been fitted with an infusion set (not shown), the cap23 removed and the piercing member 3 attached directly to the femaleluer part of the infusion set. The male luer part 15 fits into thefemale part and is held there by friction in the usual way. The plunger2 is then depressed to inject the solution in the barrel via the bore 10and opening 13 to the infusion set. The syringe can be removed when theinjection has taken place in readiness for the next one. The plunger 2may be depressed several times to administer a full course. Then oncethe full course, of several injections at varying intervals, is completefull depression of the plunger 2 actuates the locking member 21, so thatthe syringe cannot be used again.

The syringe may also be used for the reconstitution of anhydrousvaccines. For this, the syringe is uncapped, and the piercing point 12used to pierce a seal of a container of diluent, and the plunger 2withdrawn to draw up the correct volume. The piercing point 12 is thenremoved from the diluent container, and used to pierce the seal of avial of anhydrous vaccine. The diluent is dispensed into the vial bydepression of the plunger 2. Due to the projection 20, an accurateamount of diluent can be dispensed, which is important for vaccinereconstitution. After dispensing the diluent, the piercing point iswithdrawn, and the vaccine can be drawn up by separate standardsyringes. In this case the plunger 2 of the syringe shown in the Figureswill normally be fully depressed, so that the locking member 21 will beactuated to render the syringe unusable.

1-7. (canceled)
 8. A syringe comprising a barrel having a plunger inslidable and sealing engagement therein, and a piercing member formedintegrally with said barrel, said piercing member having a bore incommunication with the distal end of said barrel, and a piercing pointand an aperture at its distal end, said distal end of said piercingmember being formed with an external taper comprising a male luer partcompatible with an infusion set, wherein the length of said distal endof said piercing member distally of a predetermined attachment diameterof said male luer part is chosen so that said end of the piercing memberengages with a part of a standard metal syringe needle before a femaleluer part on said needle reaches said attachment diameter.
 9. A syringeas claimed in claim 8, wherein said syringe barrel and said piercingmember are moulded in one piece.
 10. A syringe as claimed in claim 8,wherein said taper angle of said male luer part of said piercing memberis about 6°, at said predetermined attachment diameter.
 11. A syringe asclaimed in any claim 8, wherein said barrel has at said distal end areduced diameter portion, to which said piercing member is attached. 12.A syringe as claimed in claim 11, wherein an external diameter of saidpiercing member is less than said reduced diameter portion of saidbarrel.
 13. A syringe as claimed in claim 12, wherein a protective capis provided to fit over said piercing member, and is retained by saidreduced diameter portion of the barrel.
 14. A syringe as claimed inclaim 8, wherein said plunger comprises a rod carrying a head, said headhaving a seal mounted thereon for engagement with the internal surfaceof said barrel, and a distal side of said head being formed with aprojection fitting into said bore of said piercing member as saidplunger is moved distally.